Palacio Haedo, Gothic Revival mansion near Plaza San Martín, Buenos Aires, Argentina.

Palacio Haedo is a Gothic Revival building occupying a triangular site on Avenida Santa Fe in Buenos Aires, distinguished by its twin towers that rise prominently above the surrounding structures. The facade displays French Neo-Gothic architectural details carefully composed to emphasize the building's important corner position.

The building was constructed in 1883 for Colonel Reinaldo Villar and later acquired by Banco Popular Argentino, eventually serving as the headquarters for managing Argentina's national parks. This succession of owners shows how grand city residences were repurposed to serve different institutional roles throughout the 20th century.

The building is popularly but wrongly called "Palacio Haedo"; the error arose from misreading the 1881 deed, which sold the old low house, not Giuseppe Maraini's small two-towered castle. The entrance glass, a few steps above the street door, carries the initials of Colonel Reinaldo Villar.

The building sits opposite Plaza San Martín and near Torre Monumental, making it accessible through multiple public transportation options in downtown Buenos Aires. Its location on Avenida Santa Fe means visitors can easily spot it while walking through this central neighborhood.

The building's popular name is a mistake: the 1881 deed sold to Colonel Reinaldo Villar was the old low house, not Giuseppe Maraini's small two-towered castle, as the entry numbers on Santa Fe street show. The error was repeated in a 2021 Argentina.gob.ar article. The entrance glass panes, a few steps above the street door, carry Villar's initials.